If your application is written to be audited, especially if it generates application events, it is an audit-aware application. There is no requirement that any connected database be enabled for auditing in order to run an audit-aware application. However, no audit events, including explicit application events, are generated for the application unless at least one connected database has auditing enabled.
However, if you use auditing, it is typically critical to your application environment. If your application requires auditing to be enabled before it can run, you can verify that this is the case using the AUDIT-ENABLED function. This function can verify that at least one of the connected databases in the ABL session is audit-enabled, and you can code a response accordingly.
For more information on enabling a database for auditing, see OpenEdge Getting Started: Core Business Services - Security and Auditing.